Moderate sodium restriction and potassium supplementation in essential hypertension.

Continuous 24 h arterial blood pressure and vasoactive hormones were measured in twelve patients with essential hypertension after 4 weeks on a control sodium intake (180 mmol/day) and after similar periods of sodium restriction (80 mmol/day) and potassium supplementation (200 mmol/day). Sodium restriction was associated with variable blood pressure changes in individual patients and a small reduction in 24 h mean pressure of 4/3 mmHg. The greatest fall in blood pressure with sodium restriction was seen in those patients with the least rise in renin. Potassium supplementation was associated with variable individual blood pressure changes and a trivial reduction in mean 24 h pressures (0.1/0.8 mmHg). Mean 24 h plasma aldosterone concentration was significantly higher during sodium restricted and potassium-supplemented diets, compared to control levels, but other vasoactive hormones were unchanged.